Preliminary study of ciprofloxacin in active Crohn's disease

Antibiotics and inflammatory bowel diseases

Inflammatory bowel diseases are characterized by an altered composition of gut microbiota (dysbiosis) that may contribute to their development. Antibiotics can alter the bacterial flora, and a link between antibiotic use and onset of Crohn's disease (CD), but not ulcerative colitis, has been reported. The hypothesis that Mycobacterium avium subspecies paratuberculosis (MAP) could be an etiologic agent of CD has not been confirmed by a large study on patients treated by an association of antibiotics active against MAP. The observations supporting a role of intestinal microbiota in CD pathogenesis provide the rationale for a therapeutic manipulation of the intestinal flora through the employment of antibiotics. However, current data do not strongly support a therapeutic benefit from antibiotics, and there is still controversy regarding their use as primary therapy for treatment of acute flares of CD, and for postoperative recurrence prevention. Nevertheless, clinical practice and some studies suggest that a subgroup of patients with colonic involvement, early disease, and abnormal laboratory test of inflammation may respond better to antibiotic treatment. Since their long-term use is frequently complicated by a high rate of side effects, the use of antibiotics that work locally appears to be promising.

Clinical consequences of diet-induced dysbiosis

Various disease states are associated with an imbalance of protective and pathogenic bacteria in the gut, termed dysbiosis. Current evidence reveals that dietary factors affect the microbial ecosystem in the gut. Changes to community structure of the intestinal microbiota are not without consequence considering the wide effects that the microbes have on both local and systemic immunity. The goal of this review is to give insight into the importance of gut microbiota in disease development and the possible therapeutic interventions in clinical settings. We introduce the complex tripartite relationship between diet, microbes and the gut epithelium. This is followed by a summary of clinical evidence of diet-induced dysbiosis as a contributing factor in the development of gastrointestinal diseases like inflammatory bowel disease, irritable bowel syndrome and colorectal cancer, as well as systemic diseases like obesity, diabetes, atherosclerosis and nonalcoholic fatty liver disease. Finally, the current dietary and microbial interventions to promote a healthy microbial profile will be reviewed.

Ciprofloxacin for the prevention of postoperative recurrence in patients with Crohn's disease: a randomized, double-blind, placebo-controlled pilot study

BACKGROUND

The commensal bacterial flora plays a critical role in the postoperative recurrence of Crohn's disease (CD). We conducted a randomized, double-blind, placebo-controlled 6-month pilot trial of ciprofloxacin for the prevention of endoscopic recurrence in patients with CD who underwent surgery.

METHODS

Thirty-three patients with CD, who had undergone surgery with ileocolonic anastomosis within the previous 2 weeks, were randomized to treatment with ciprofloxacin (500 mg twice daily) or placebo tablets for 6 months. Endpoints were endoscopic recurrence at 6 months and safety and tolerability of long-term ciprofloxacin therapy.

RESULTS

Thirty-three patients were randomized; 14 patients discontinued the study early. Significant endoscopic recurrence was observed in 3 of 9 patients (33%) in the ciprofloxacin group and 5 of 10 patients (50%) in the placebo group at 6 months after surgery (P < 0.578). The intention-to-treat analysis demonstrated endoscopic recurrence in 11 of 17 patients (65%) in the ciprofloxacin group and 11 of 16 patients (69%) in the placebo group at month 6 (P < 0.805). Thirty-six adverse events occurred in 19 of 33 patients (58%). Possible drug-associated adverse events occurred significantly more often in the ciprofloxacin group (P < 0.043), leading to study drug discontinuation in 24% (4 of 17) and 6% of patients (1 of 16) in the ciprofloxacin and placebo groups, respectively (P < 0.166).

CONCLUSIONS

In this pilot study, ciprofloxacin was not more effective than placebo for the prevention of postoperative recurrence in patients with CD. Long-term ciprofloxacin therapy is limited by drug-associated side effects. Future studies in postoperative prevention of CD should evaluate antibiotic approaches with a more favorable safety profile.

Long-term antibiotic therapy in late onset pouch-urethral fistula after ileoanal anastomosis for ulcerative colitis may be effective and well tolerated

A 25-year-old male patient underwent restorative proctocolectomy and ileoanal anastomosis in 1991 for refractory ulcerative colitis. In February 2001, he presented with pneumaturia, faecaluria, pelvic 'pressure' and watery diarrhoea caused by passage of urine through the anal canal. A fistula between the pouch and the membranous urethra was demonstrated by a pouchogram contrast study. In October 2002, he was started on ciprofloxacin 250 mg once daily and metronidazole 400 mg twice daily. Apart from a short break in 2003 the patient has remained on this regimen until the time of writing (now over 10 years) and has had sustained remission, excellent quality of life and no adverse effects.

Microbial manipulation as primary therapy for Crohn's disease

While antimicrobials are clinically effective in preventing post-operative recurrence, the role for antibiotics in primary therapy for Crohn’s disease (CD) remains unclear. The recent multicenter phase 2 trial by Prantera et al received wide attention because it demonstrated an increase in the week 12 remission rate in patients with moderately active CD treated with rifaximin and renewed interest in microbial manipulation as primary therapy for CD. In this commentary, we discuss aspects of durability, immune cell polarization, and safety of microbial manipulation as primary therapy for CD.

The role of antimicrobials in Crohn's disease

This review summarizes literature regarding the role of antimicrobials for induction and maintenance of Crohn's disease (CD) remission. PubMed was searched (1966 to October 2012) for controlled trials involving adults and written in English. Five of the 13 identified studies showed benefit with the use of ciprofloxacin, metronidazole and rifaximin for induction of remission. Eight studies showed no benefit using ciprofloxacin, metronidazole, combination of metronidazole and ciprofloxacin or clarithromycin and rifaximin. Four of the five studies showed benefit based on colonic location. Perianal CD with draining fistulas responded in one of two studies. Two studies in postileocolonic resection demonstrated benefit of metronidazole or ornidazole in reducing CD recurrence. Antimicrobials, especially metronidazole, are promising for inducing remission in patients with colonic CD and preventing recurrence in postileocolonic resection.

Use of antibiotics in the treatment of Crohn’s disease

Many data coming from animal models and clinical observations support an involvement of intestinal microbiota in the pathogenesis of Crohn’s disease (CD). It is hypothesized in fact, that the development of chronic intestinal inflammation is caused by an abnormal immune response to normal flora in genetically susceptible hosts. The involvement of bacteria in CD inflammation has provided the rationale for including antibiotics in the therapeutic armamentarium. However, randomized controlled trials have failed to demonstrate an efficacy of these drugs in patients with active uncomplicated CD, even if a subgroup of patients with colonic location seems to get benefit from antibiotics. Nitroimidazole compounds have been shown to be efficacious in decreasing CD recurrence rates in operated patients, and the use of metronidazole and ciprofloxacin is recommended in perianal disease. However, the appearance of systemic side effects limits antibiotic long-term employment necessary for treating a chronic relapsing disease. Rifaximin, characterized by an excellent safety profile, has provided promising results in inducing remission of CD.

Multidrug resistance is common in Escherichia coli associated with ileal Crohn's disease

BACKGROUND

Escherichia coli is increasingly implicated in the pathogenesis of ileal Crohn's disease (ICD), offering a potential therapeutic target for disease management. Empirical antimicrobial targeting of ileal E. coli has advantages of economy and speed of implementation, but relies on uniform susceptibility of E. coli to routinely selected antimicrobials to avoid apparent treatment failure. Therefore, we examined the susceptibility of ileal E. coli to such antimicrobials.

METHODS

E. coli from 32 patients with ICD and 28 with normal ileum (NI) were characterized by phylogroup, pathotype, antimicrobial susceptibility, and presence of antimicrobial resistance genes.

RESULTS

In all, 17/32 ICD and 12/28 NI patients harbored ≥ 1 E. coli strain; 10/24 E. coli strains from ICD and 2/14 from NI were nonsuscepti-ble to ≥ 1 antimicrobial in ≥ 3 categories (multidrug-resistant). Resistance to amoxicillin/clavulanic-acid, cefoxitin, chloramphenicol, ciprofloxa-cin, gentamicin, and rifaximin was restricted to ICD, with 10/24 strains from 8/17 patients resistant to ciprofloxacin or rifaximin (P < 0.01). Adherent-invasive E. coli (AIEC) were isolated from 8/32 ICD and 5/28 NI, and accounted for 54% and 43% of E. coli strains in these groups. In all, 8/13 AIEC strains from ICD (6/8 patients) versus 2/6 NI (2/5 patients) showed resistance to the macrophage-penetrating antimicrobials ciprofloxacin, clarithromycin, rifampicin, tetracycline, and trimethoprim/sulfamethoxazole. Resistance was associated with tetA, tetB, tetC, bla-(TEM), bla(oxa)-1, sulI, sulII, dhfrI, dhfrVII, ant(3″)-Ia, and catI genes and prior use of rifaximin (P < 0.01).

CONCLUSIONS

ICD-associated E. coli frequently manifest resistance to commonly used antimicrobials. Clinical trials of antimicrobials against E. coli in ICD that are informed by susceptibility testing, rather than empirical selection, are more likely to demonstrate valid outcomes of such therapy.

Meta-analysis of broad-spectrum antibiotic therapy in patients with active inflammatory bowel disease

Patients with Crohn's disease (CD) or ulcerative colitis (UC) undergo various therapies, including antibiotic therapy. This meta-analysis of controlled clinical trials was conducted to evaluate whether the use of antibacterial therapy improves the clinical symptoms of inflammatory bowel disease (IBD). The Medline and Scopus databases were searched and a systematic review was performed. Randomized, controlled trials in which antibiotic therapy was compared with placebo were investigated. A total of 10 randomized, placebo-controlled clinical trials for CD were included in the meta-analysis. The pooling of the data from these trials yielded an odds ratio (OR) of 1.35 [95% confidence interval (CI), 1.16-1.58] for antibiotic therapy compared with placebo in patients with CD. Furthermore, nine randomized placebo-controlled clinical trials for UC matched our criteria and were included in the analysis. The pooling of the data from these trials yielded an OR of 2.17 (95% CI, 1.54-3.05) in favor of antibiotic therapy. These results suggest that antibiotics improve clinical outcomes in patients with IBD.

Rifaximin-extended intestinal release induces remission in patients with moderately active Crohn's disease

BACKGROUND & AIMS

Bacteria might be involved in the development and persistence of inflammation in patients with Crohn's disease (CD), and antibiotics could be used in therapy. We performed a clinical phase 2 trial to determine whether a gastroresistant formulation of rifaximin (extended intestinal release [EIR]) induced remission in patients with moderately active CD.

METHODS

We performed a multicenter, randomized, double-blind trial of the efficacy and safety of 400, 800, and 1200 mg rifaximin-EIR, given twice daily to 402 patients with moderately active CD for 12 weeks. Data from patients given rifaximin-EIR were compared with those from individuals given placebo, and collected during a 12-week follow-up period. The primary end point was remission (Crohn's Disease Activity Index <150) at the end of the treatment period.

RESULTS

At the end of the 12-week treatment period, 62% of patients who received the 800-mg dosage of rifaximin-EIR (61 of 98) were in remission, compared with 43% of patients who received placebo (43 of 101) (P = .005). A difference was maintained throughout the 12-week follow-up period (45% [40 of 89] vs 29% [28 of 98]; P = .02). Remission was achieved by 54% (56 of 104) and 47% (47 of 99) of the patients given the 400-mg and 1200-mg dosages of rifaximin-EIR, respectively; these rates did not differ from those of placebo. Patients given the 400-mg and 800-mg dosages of rifaximin-EIR had low rates of withdrawal from the study because of adverse events; rates were significantly higher among patients given the 1200-mg dosage (16% [16 of 99]).

CONCLUSIONS

Administration of 800 mg rifaximin-EIR twice daily for 12 weeks induced remission with few adverse events in patients with moderately active CD.

Treatment of inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which includes Crohn's disease (CD) and ulcerative colitis (UC). These diseases have become important health problems. Medical therapy for IBD has advanced dramatically in the last decade with the introduction of targeted biologic therapies, the optimization of older therapies, including rugs such as immunomodulators and 5-aminosalicylic acid (5-ASA), and a better understanding of the mucosal immune system and the genetics involved in the pathogenesis of IBD. The goal of IBD therapy is to induce and maintain remission. The current treatment paradigm involves a step-up approach, moving to aggressive, powerful therapies only when milder therapies with fewer potential side effects fail or when patients declare themselves to have an aggressive disease. This review focuses on the current treatments for inflammatory bowel disease.

Optimization of conventional therapy in patients with IBD

The majority of patients with IBD use conventional therapy (namely, aminosalicylates, antibiotics, corticosteroids and immunomodulatory agents) for prolonged periods of time, to both induce and maintain remission. Treatment paradigms in IBD have evolved towards a rapid escalation of therapy to achieve stringent goals, including mucosal healing and a reduction in the need for hospital admission and surgery. In this context, the failure to optimize conventional therapy can lead to a potentially effective treatment being abandoned too early, which is undesirable when only a limited number of drugs are effective in the management of IBD, and could also lead to patients being unnecessarily exposed to potentially toxic and/or expensive biologic drugs. This Review provides an overview of the many ways in which conventional therapy can be optimized, and describes strategies to improve adherence to drug regimens, such as simplifying the dosing regimen, optimizing drug delivery and dose, and tailoring medication on the basis of metabolite levels.

A meta-analysis of randomized controlled trials comparing antibacterial therapy with placebo in Crohn's disease

BACKGROUND

Antibacterial therapy has been investigated in several randomized, clinical trials compared with placebo for the management of Crohn's disease. Evidences for the efficacy of intervention are increasingly required.

OBJECTIVES

To conduct a meta-analysis of randomized trials to compare the effects of antibacterial therapy versus placebo in patients with Crohn's disease.

SEARCH STRATEGY

A systematic literature search of Pubmed, EMBASE, Cochrane Library (April 1966 to July 2009) was conducted using specific search terms.

SELECTION CRITERIA

Eligible studies were randomized controlled trials comparing antibacterial (antimycobacterial and broad-spectrum antibiotic) therapy with placebo.

DATA COLLECTION AND ANALYSIS

Studies were reviewed to determine the number of participants, mean follow-up, and the odds ratios (OR) for primary end point of clinical remission and clinical response were also abstracted. The meta-analysis was performed using a fixed-effects model or a randomized-effects model according to the degree of heterogeneity.

RESULTS

Eleven randomized placebo-controlled clinical trials with 668 participants (364 patients in the treatment group and, 304 patients in the placebo group) were identified. Antimycobacterial agents were used in four of the trials and broad-spectrum antibiotics were used in the other seven trials. Pooled analysis showed no significant differences in the rates of clinical remission [OR = 1.28, 95% confidence interval (CI): 0.87-1.90, P = 0.214] and clinical response (OR = 1.52, 95% CI: 0.91-2.55, P = 0.108) after receiving antibacterial treatment for 3 months or longer.

CONCLUSION

In this meta-analysis, no evidence of benefit for antibiotics in patients with Crohn's disease was found.

Role of conventional therapies in the era of biological treatment in Crohn’s disease

Outstanding progress regarding the pathophysiology of Crohn’s disease (CD) has led to the development of innovative therapeutic concepts. Numerous controlled trials have been performed in CD. This review concentrates on the results of randomized, placebo-controlled trials, and meta-analyses when available, that provide the highest degree of evidence. Current guidelines on the management of CD recommend a step-up approach to treatment involving the addition of more powerful therapies as the severity of disease and refractoriness to therapy increase. The advent of biological drugs has opened new therapeutic horizons for treating CD, modifying the treatment goals. However, the large majority of patients with CD will be managed through conventional therapy, even if they are a prelude to biological therapy.

Current and emerging drugs for the treatment of inflammatory bowel disease

During the last decade a large number of biological agents against tumor necrosis factor-α (TNF-α), as well as many biochemical substances and molecules specifically for the medical treatment of patients with inflammatory bowel disease (IBD), have been developed. This enormous progress was a consequence of the significant advances in biotechnology along with the increased knowledge of the underlying pathophysiological mechanisms involved in the pathogenesis of IBD. However, conventional therapies remain the cornerstone of treatment for most patients. During recent years conventional and biologic IBD therapies have been optimized. Newer mesalazine formulations with a reduced pill size and only one dose per day demonstrate similar efficacy to older formulations. New corticosteroids retain the efficacy of older corticosteroids while exhibiting a higher safety profile. The role of antibiotics and probiotics has been further clarified. Significant progress in understanding thiopurine metabolism has improved the effective dose along with adjunctive therapies. Quite a large number of substances and therapies, including biologic agents other than TNF-α inhibitors, unfractionated or low-molecular-weight heparin, omega-3 polyunsaturated fatty acids, microbes and microbial products, leukocytapheresis, and other substances under investigation, could offer important benefits to our patients. In this paper we review the established and emerging therapeutic strategies in patients with Crohn's disease and ulcerative colitis.

Antibiotic therapy in inflammatory bowel disease: a systematic review and meta-analysis

The etiology of inflammatory bowel disease (IBD) is unknown but may relate to an unidentified bacterial pathogen or an immunological reaction to gut microbiota. Antibiotics have therefore been proposed as a therapy for Crohn's disease (CD) and ulcerative colitis (UC) to induce remission in active disease to prevent relapse. Current data are conflicting and we therefore conducted a systematic review of randomized controlled trials (RCTs) evaluating antibiotics in IBD. Only parallel group RCTs were considered eligible. Studies with adult patients receiving any dose of therapy for at least 7 days and up to 16 weeks for active disease, or at least 6 months of follow-up for preventing relapse in quiescent disease were analyzed. We included any antibiotics alone or in combination using predefined definitions of remission and relapse. Two reviewers independently assessed eligibility and extracted data. The primary outcome was remission or relapse using an intention-to-treat methodology. The data were summarized using relative risk (RR) and pooled using a random effects model. For active CD, there were 10 RCTs involving 1,160 patients. There was a statistically significant effect of antibiotics being superior to placebo (RR of active CD not in remission=0.85; 95% confidence interval (CI)=0.73-0.99, P=0.03). There was moderate heterogeneity between results (I(2)=48%) and a diverse number of antibiotics were tested (anti-tuberculosis therapy, macrolides, fluroquinolones, 5-nitroimidazoles, and rifaximin) either alone or in combination. Rifamycin derivatives either alone or in combination with other antibiotics appeared to have a significant effect at inducing remission in active CD. In perianal CD fistula there were three trials evaluating 123 patients using either ciprofloxacin or metronidazole. There was a statistically significant effect in reducing fistula drainage (RR=0.8; 95% CI=0.66-0.98) with no heterogeneity (I(2)=0%) and an number needed to treat 5 (95% CI=3-20). For quiescent CD, there were 3 RCTs involving 186 patients treated with different antibiotics combinations (all including antimycobacterials) vs. placebo. There was a statistically significant effect in favor of antibiotics vs. placebo (RR of relapse=0.62; 95% CI=0.46-0.84), with no heterogeneity (I(2)=0%). In active UC, there were 9 RCTs with 662 patients and there was a statistically significant benefit for antibiotics inducing remission (RR of UC not in remission=0.64; 95% CI=0.43-0.96). There was moderate heterogeneity (I(2)=69%) and antibiotics used were all different single or combination drugs. Antibiotic therapy may induce remission in active CD and UC, although the diverse number of antibiotics tested means the data are difficult to interpret. This systematic review is a mandate for further trials of antibiotic therapy in IBD.

The role of bacteria and pattern-recognition receptors in Crohn's disease

Crohn's disease is widely regarded as a multifactorial disease, and evidence from human and animal studies suggests that bacteria have an instrumental role in its pathogenesis. Comparison of the intestinal microbiota of patients with Crohn's disease to that of healthy controls has revealed compositional changes. In most studies these changes are characterized by an increase in the abundance of Bacteroidetes and Proteobacteria and a decrease in that of Firmicutes. In addition, a number of specific mucosa-associated bacteria have been postulated to have a role in Crohn's disease, including Mycobacterium avium subspecies paratuberculosis, adherent and invasive Escherichia coli, Campylobacter and Helicobacter species. The association between mutations in pattern-recognition receptors (Toll-like receptors and Nod-like receptors) and autophagy proteins and Crohn's disease provides further evidence to suggest that defective sensing and killing of bacteria may drive the onset of disease. In this Review, we present recent advances in understanding the role of bacteria and the contribution of pattern-recognition receptors and autophagy in the pathogenesis of Crohn's disease.

What is the optimal therapy for Crohn's disease: step-up or top-down?

Crohn's disease (CD) is an idiopathic chronic inflammatory disorder of the digestive tract, which is incurable. Present therapeutic guidelines follow a sequential step-up approach that focuses on treating acute disease or 'inducing clinical remission' and subsequently aims to 'maintain clinical response'. In view of the chronic relapsing-remitting disabling disease course, new treatment approaches have been sought with the ultimate end point of disease course modification and mucosal healing. A recent preliminary study from D'Haens et al. has provided evidence suggesting that reversing the treatment paradigm from a 'step-up' to a 'top-down' approach may positively alter the natural course of this illness. Their findings indicate that early use of biologic therapy, in combination with immunomodulators, resulted in remission occuring more rapidly than the conventional 'step-up' treatment, with a longer time period to relapse, a decreased need for treatment with corticosteroids, a faster reduction in clinical symptoms, rapid decline in biochemical inflammatory markers (C-reactive protein) and improved endoscopic mucosal healing. These results, supported by previous studies on infliximab use, may hold a promising outcome of fewer stricturing complications, hospitalizations and surgeries for patients with CD. However, we need to better define the timing and candidates for the 'top-down' approach as we are still uncertain about the safety data and the long-term benefits if biologic agents are given as routine maintenance treatment, since most of the trials in CD have been short term, and approximately 30% of patients might have been overtreated. Future clinical trials will be crucial in answering these questions.

Adjunctive antibiotic therapy with rifaximin may help reduce Crohn's disease activity

AIMS

Enteric bacteria are thought to contribute to the pathogenesis of Crohn's disease, and antibiotics may be an effective therapy. This study examines the efficacy of the nonsystemic (<0.4% absorbed) antibiotic rifaximin for inducing remission in patients with Crohn's disease.

METHODS

Data from charts of patients with Crohn's disease who received rifaximin between 2001 and 2005 and had a Crohn's disease activity index score > or =220 at the time of rifaximin initiation were analyzed. The use of concomitant medications (e.g., steroids, anti-inflammatory agents) was allowed.

RESULTS

In the 68 patient charts analyzed, the median duration of rifaximin treatment was 16.6 weeks, and the majority of patients (94%) received rifaximin 600 mg/day. Eighteen patients (26%) received rifaximin monotherapy, and 31 patients (46%) received concomitant steroids. The median baseline Crohn's disease activity index score at the time of rifaximin initiation was 265 (range, 220-460), and the mean duration of Crohn's disease was 17 years (range, 1-50 years). Crohn's disease remission occurred in 65% of patients. A 70% remission rate was achieved in patients who did not receive steroids, versus 58% in patients who received steroids. Clinical improvements continued 4 months after rifaximin initiation. Remission was achieved in 67% of patients who received rifaximin monotherapy.

CONCLUSIONS

Rifaximin therapy was associated with clinical improvement in patients with Crohn's disease and may be a useful treatment option to consider for inducing and maintaining remission.

Evolving inflammatory bowel disease treatment paradigms: top-down versus step-up

Crohn disease (CD) and ulcerative colitis (UC) comprise a group of inflammatory disorders of the gastrointestinal tract that can vary in severity of disease, anatomic extent of inflammation, presence and nature of extraintestinal manifestations, and response to therapeutic approaches. There have been attempts to classify CD based on the location and behavior of disease. Advances in understanding of genetic susceptibility to inflammatory bowel disease (IBD) suggest that CD and UC may represent a continuum of overlapping disorders. This has led to an attempt to classify IBD on clinical, molecular, and serologic grounds. Differences in clinical, genetic, and immunologic profiles may require more targeted, refined treatment approaches to help clinicians make decisions regarding recently introduced biologic agents. This article provides an overview of the current approaches to therapy for CD and UC and focuses on the evidence supporting the rationale for changing paradigms in the management of IBD, including mucosal healing as an end point and earlier use of immunosuppressive and biologic agents, particularly in CD (so-called top-down therapy).

Evolving inflammatory bowel disease treatment paradigms: top-down versus step-up

Crohn disease (CD) and ulcerative colitis (UC) comprise a group of inflammatory disorders of the gastrointestinal tract that can vary in severity of disease, anatomic extent of inflammation, presence and nature of extraintestinal manifestations, and response to therapeutic approaches. There have been attempts to classify CD based on the location and behavior of disease. Advances in understanding of genetic susceptibility to inflammatory bowel disease (IBD) suggest that CD and UC may represent a continuum of overlapping disorders. This has led to an attempt to classify IBD on clinical, molecular, and serologic grounds. Differences in clinical, genetic, and immunologic profiles may require more targeted, refined treatment approaches to help clinicians make decisions regarding recently introduced biologic agents. This article provides an overview of the current approaches to therapy for CD and UC and focuses on the evidence supporting the rationale for changing paradigms in the management of IBD, including mucosal healing as an end point and earlier use of immunosuppressive and biologic agents, particularly in CD (so-called top-down therapy).

Negative interactions with the microbiota: IBD

Mucosal surfaces are colonized by a complex microbiota that provides beneficial functions under normal physiological conditions, but is capable of contributing to chronic inflammatory disease in susceptible individuals. Of the mucosal tissues, the mammalian intestine harbors an especially high number of microbes with a remarkable diversity. Inflammatory bowel disease (IBD) is a group of chronic relapsinginflammatory disorders of the intestinal mucosa. Evidence from human studies and animal models provides compelling support that intestinal microbes play a key role in disease pathogenesis. While the existence a specific causative pathogen is possible, it appears more likely that intestinal microbes normally present as commensal microbiota may trigger inflammation and perpetuate disease in genetically susceptible individuals. There may be also a shift in the makeup of the commensal flora to a nonphysiologic composition that is more prone to disease (termed dysbiosis). Evidence supports that genetic susceptibility stems from one or more defects in mucosal immune functions, including microbe recognition, barrier function, intercellular communication and antimicrobial effector mechanisms. It is quite plausible to imagine that the chronic inflammation of IBD may in some cases be a normal immune response to an abnormal adherent invasive microbiota and in other cases an over exuberant immune response to an otherwise normal commensal microbiota.

Intestinal bacteria and inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the two principal forms of inflammatory bowel disease (IBD). Animal studies show that bacteria are involved in the etiology of IBD, and much is now known about the inflammatory processes associated with CD and UC, as well as the underlying genetic, environmental, and lifestyle issues that can affect an individual's predisposition to these diseases. However, while a number of candidate microorganisms have been put forward as causative factors in IBD, the primary etiologic agents are unknown. This review discusses the potential role of luminal and mucosal microbial communities in the etiology of IBD, and outlines studies that have been made using a variety of biotherapeutic therapies, involving the use of antibiotics, probiotics, prebiotics, and synbiotics.

Management of Crohn's disease in adults

Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of published literature. When data that will withstand objective scrutiny are not available, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health-care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. Expert opinion is solicited from the outset for the document. The quality of evidence upon which a specific recommendation is based is as follows: Grade A: Homogeneous evidence from multiple well-designed randomized (therapeutic) or cohort (descriptive) controlled trials, each involving a number of participants to be of sufficient statistical power. Grade B: Evidence from at least one large well-designed clinical trial with or without randomization, from cohort or case-control analytic studies, or well-designed meta-analysis. Grade C: Evidence based on clinical experience, descriptive studies, or reports of expert committees. The Committee reviews guidelines in depth, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time.

Bacteria and bacterial rRNA genes associated with the development of colitis in IL-10(-/-) mice

BACKGROUND

Microorganisms appear to play important yet ill-defined roles in the etiology of inflammatory bowel disease (IBD). This study utilized a novel population-based approach to identify bacteria and bacterial rRNA genes associated with the development of colitis in IL-10(-/-) mice.

METHODS

Mice were housed in 2 environments: a community mouse facility where the mice were fed nonsterile chow (Room 3) and a limited access facility where the mice were fed sterile chow (Room 4). Every month the disease activity levels were assessed and fecal bacterial compositions were analyzed. At the end of the experiments histological and bacterial analyses were performed on intestinal tissue.

RESULTS

Although disease activity increased over time in both environments, it progressed at a faster rate in Room 3 than Room 4. Culture and culture-independent bacterial analyses identified several isolates and phylotypes associated with colitis. Two phylotypes (GpC2 and Gp66) were distinguished by their negative associations with disease activity in fecal and tissue samples. Notably, rRNA genes from these phylotypes had high sequence identity (99%) to an rRNA gene from a previously described flagellated Clostridium (Lachnospiraceae bacterium A4).

CONCLUSIONS

The negative associations of these 2 phylotypes (GpC2 and Gp66) suggest that these bacteria were being immunologically targeted, consistent with prior findings that the Lachnospiraceae bacterium A4 bears a prevalent flagellar antigen for disease-associated immunity in murine immune colitis and human Crohn's disease. Identification of these associations suggests that the experimental approach used in this study will have considerable utility in elucidating the host-microbe interactions underlying IBD.

Evidence for the involvement of infectious agents in the pathogenesis of Crohn's disease

Many advances have been made in the understanding of Crohn's disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lymphocyte-driven disease characterized by the presence of a complex cocktail of interacting cytokines, chemokines and other mediators produced by a variety of cell types. Prevailing theories of CD pathogenesis suggest that patients' T-lymphocytes are inappropriately activated in the setting of an immune imbalance, which is itself caused by an unfortunate confluence of genetic and environmental factors. The T-cell response then leads to the chronic inflammation characteristic for the disease. Various environmental factors may play a role in the development of CD, but microbes are most consistently implied. This theory is based on epidemiological, clinicopathological, genetic and experimental evidence. Despite the abundance of arguments for the implication of bacteria in the aetiopathogenesis of CD, the precise role of bacteria in this disease still remains elusive. Three not necessarily mutually exclusive theories have been proposed: (1) an unidentified persistent pathogen; (2) an abnormally permeable mucosal barrier leading to excessive bacterial translocation; and (3) a breakdown in the balance between putative "protective" versus "harmful" intestinal bacteria ("dysbiosis"). At present, one cannot exclude with certainty any of these three proposed hypotheses; they may all apply to CD to a certain extent.

Treatment of inflammatory bowel disease: a review of medical therapy

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal tract. While a cure remains elusive, both can be treated with medications that induce and maintain remission. With the recent advent of therapies that inhibit tumor necrosis factor (TNF) alpha the overlap in medical therapies for UC and CD has become greater. Although 5-ASA agents have been a mainstay in the treatment of both CD and UC, the data for their efficacy in patients with CD, particularly as maintenance therapy, are equivocal. Antibiotics may have a limited role in the treatment of colonic CD. Steroids continue to be the first choice to treat active disease not responsive to other more conservative therapy; non-systemic steroids such as oral and rectal budesonide for ileal and right-sided CD and distal UC respectively are also effective in mild-moderate disease. 6-mercaptopurine (6-MP) and its prodrug azathioprine are steroid-sparing immunomodulators effective in the maintenance of remission of both CD and UC, while methotrexate may be used in both induction and maintenance of CD. Infliximab and adalimumab are anti-TNF agents approved in the US and Europe for the treatment of Crohn's disease, and infliximab is also approved for the treatment of UC.

Replication of Colonic Crohn's Disease Mucosal Escherichia coli Isolates within Macrophages and Their Susceptibility to Antibiotics

There is increasing evidence that Escherichia coli organisms are important in Crohn's disease (CD) pathogenesis. In CD tissue they are found within macrophages, and the adherent-invasive CD ileal E. coli isolate LF82 can replicate inside macrophage phagolysosomes. This study investigates replication and antibiotic susceptibility of CD colonic E. coli isolates inside macrophages. Replication of CD colonic E. coli within J774-A1 murine macrophages and human monocyte-derived macrophages (HMDM) was assessed by culture and lysis after gentamicin killing of noninternalized bacteria and verified by electron microscopy (EM). All seven CD colonic isolates tested replicated within J774-A1 macrophages by 3 h (6.36-fold +/- 0.7-fold increase; n = 7 isolates) to a similar extent to CD ileal E. coli LF82 (6.8-fold +/- 0.8-fold) but significantly more than control patient isolates (5.2-fold +/- 0.25-fold; n = 6; P = 0.006) and E. coli K-12 (1.0-fold +/- 0.1-fold; P < 0.0001). Replication of CD E. coli HM605 within HMDM (3.9-fold +/- 0.7-fold) exceeded that for K-12 (1.4-fold +/- 0.2-fold; P = 0.03). EM showed replicating E. coli within macrophage vacuoles. Killing of HM605 within J774-A1 macrophages following a 3-h incubation with antibiotics at published peak serum concentrations (C(max)) was as follows: for ciprofloxacin, 99.5% +/- 0.2%; rifampin, 85.1% +/- 6.6%; tetracycline, 62.8% +/- 6.1%; clarithromycin, 62.1% +/- 5.6% (all P < 0.0001); sulfamethoxazole, 61.3% +/- 7.0% (P = 0.0007); trimethoprim, 56.3% +/- 3.4% (P < 0.0001); and azithromycin, 41.0% +/- 10.5% (P = 0.03). Ampicillin was not effective against intracellular E. coli. Triple antibiotic combinations were assessed at 10% C(max), with ciprofloxacin, tetracycline, and trimethoprim causing 97% +/- 0.0% killing versus 86% +/- 2.0% for ciprofloxacin alone. Colonic mucosa-associated E. coli, particularly CD isolates, replicate within macrophages. Clinical trials are indicated to assess the efficacy of a combination antibiotic therapy targeting intramacrophage E. coli.

Medical management of Crohn's disease

The clinical course of Crohn's disease (CD) is characterized by unpredictable phases of disease activity and quiescence. The majority of CD patients experience mild to moderate disease or are in clinical remission over significant periods during the course of their disease. These patients can be treated conservatively with 5-aminosalicylates or budesonide depending on the disease location. Those patients with more severe forms of the disease who require corticosteroids should be treated more aggressively with early introduction of immunomodulator and/or biologic therapy, which may help to prevent the complications associated with CD. It has been suggested that therapies directed at mucosal healing may favorably modify the natural history of CD. As newer, more effective medications become available and new therapeutic approaches are introduced (top-down therapy), mucosal healing, and not solely clinical remission, may well become the preferred treatment objective.

Medical management of mild to moderate Crohn's disease: evidence-based treatment algorithms for induction and maintenance of remission

BACKGROUND

Patients with Crohn's disease alternate between periods of active, symptomatic disease and periods of remission. The treatment goal for Crohn's disease is to induce and then maintain remission of symptoms.

AIM

To review evidence from randomized, controlled, clinical trials on medical therapies for inducing and maintaining remission in patients with mild-to-moderate Crohn's disease, and to suggest the best evidence-based approaches for induction and maintenance therapies.

METHODS

PubMed search using the following terms: sulfasalazine or salicylazosulfapyridine or aminosalicylate or aminosalicylic acid or mesalamine or mesalazine or corticosteroid or prednisone or prednisolone or methylprednisolone or budesonide or antibiotic or metronidazole or ciprofloxacin or immunosuppressive or azathioprine or mercaptopurine or thiopurine or methotrexate and Crohn's disease.

RESULTS

Randomized, controlled trials demonstrated that sulfasalazine, budesonide, and conventional corticosteroids are effective for inducing remission of mild-to-moderate Crohn's disease when administered for a period of 8-16 weeks. An ideal maintenance therapy does not currently exist.

CONCLUSIONS

Selection of maintenance therapy is based on a combination of evidence from controlled trials and patient features including disease severity and location, co-morbidities, previous response to treatment, and previous surgical resection. The options for maintenance therapy include therapy cessation and patient observation following successful induction, budesonide, or immunosuppressive therapy.

"Mind the Gap": an unmet need for new therapy in IBD

Most physicians believe that the drugs they prescribe will work in their patients and thus have made little preparation for alternative strategies in the event of failure. In the treatment of inflammatory bowel disease (IBD), achieving a remission rate of 20% to 30% or a response rate of 50% to 60% is highly acceptable. This review focuses primarily on placebo-controlled trials that evaluated "usual" treatments for IBD in terms of induction and maintenance of remission, and identifies the "gaps" (ie, the percentage of patients lacking any benefit) in currently available treatments for IBD. Approximately, 40% to 60% of patients will not benefit from the available treatments, indicating a considerable unmet need for new, more effective therapies.

Current and future therapies for inflammatory bowel disease

The introduction of biologic agents to the therapeutic arsenal has dramatically impacted the way we treat patients with inflammatory bowel disease, allowing clinicians to achieve lasting remission in patients who are unresponsive to conventional therapies. New research continues to expand our understanding of the inflammatory cascade of ulcerative colitis and Crohn's disease, revealing a host of potential therapeutic targets for intervention. As we look toward the future in this rapidly developing field, we must learn how best to incorporate these new agents into the treatment algorithm to enhance or replace conventional therapies.

Crohn's disease and its mucocutaneous involvement

Crohn's disease (CD) is a chronic inflammatory disorder primarily affecting the lower gastrointestinal tract but potentially involving the skin, musculoskeletal system, and eyes. The origin remains unknown, although diverse etiologic agents have been proposed. Characteristic pathologic appearances include the formation of "skip" lesions (discrete regions of inflamed bowel separated by uninvolved mucosae), aphthous ulceration, and fistulation; these signs relate to the presence of an underlying granulomatous transmural inflammation. Cutaneous and oral lesions frequently occur in CD. They may be classified as specific manifestations (in particular, perianal fissures, abscesses, sinuses, and fistulae in ano) with a granulomatous noncaseating inflammation on histologic examination, and nonspecific manifestations (eg, erythema nodosum, neutrophilic dermatoses) with a nonspecific histologic pattern. The diagnosis of CD is based on clinical, endoscopic, radiologic, and histopathologic features. Therapy is mainly aimed at the control of the acute disease and prevention of relapse through the use of mesalazine, corticosteroids, immunosuppressive agents and very recently, anti-tumor necrosis factor-alpha antibodies.

Open label trial of clarithromycin therapy in Japanese patients with Crohn's disease

BACKGROUND AND AIM

The pathogenesis of Crohn's disease is unclear, but many studies suggest that luminal bacteria play an important role in chronic intestinal inflammation in patients with this condition. Clarithromycin is a macrolide antibiotic with immunomodulatory activity. The aim of this study was to evaluate the effect of clarithromycin therapy in Japanese patients with Crohn's disease.

METHODS

Fourteen patients with active Crohn's disease (12 with ileocolonic, one with colonic, one with small bowel type) were treated with oral clarithromycin 200 mg twice daily for 4 weeks. Patients who showed a clinical response within 4 weeks continued the therapy for up to 24 weeks. Four patients also received azathioprine. Clinical activity was assessed with the Crohn's Disease Activity Index (CDAI) at entry and at 4, 12, and 24 weeks after starting clarithromycin.

RESULTS

The mean CDAI score at entry was 343.5. Within 4 weeks, eight (57.1%) of the 14 patients showed clinical improvement, and five (35.7%) of the eight patients achieved remission. All of those eight patients continued clarithromycin therapy after 4 weeks, and six (42.9%) were in clinical remission at 12 weeks. Of the 14 total patients, four (28.6%) continued clarithromycin for more than 24 weeks, and have remained in remission. Patients who received azathioprine concomitantly had a better response to clarithromycin therapy. No severe side-effects were observed during the study period.

CONCLUSIONS

This open label study showed encouraging results of clarithromycin therapy in Japanese patients with active Crohn's disease.

Two-year combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for Crohn's disease

BACKGROUND & AIMS

Mycobacterium avium subspecies paratuberculosis has been proposed as a cause of Crohn's disease. We report a prospective, parallel, placebo-controlled, double-blind, randomized trial of 2 years of clarithromycin, rifabutin, and clofazimine in active Crohn's disease, with a further year of follow-up.

METHODS

Two hundred thirteen patients were randomized to clarithromycin 750 mg/day, rifabutin 450 mg/day, clofazimine 50 mg/day or placebo, in addition to a 16-week tapering course of prednisolone. Those in remission (Crohn's Disease Activity Index <or=150) at week 16 continued their study medications in the maintenance phase of the trial. Primary end points were the proportion of patients experiencing at least 1 relapse at 12, 24, and 36 months.

RESULTS

At week 16, there were significantly more subjects in remission in the antibiotic arm (66%) than the placebo arm (50%; P=.02). Of 122 subjects entering the maintenance phase, 39% taking antibiotics experienced at least 1 relapse between weeks 16 and 52, compared with 56% taking placebo (P=.054). At week 104, the figures were 26% and 43%, respectively (P=.14). During the following year, 59% of the antibiotic group and 50% of the placebo group relapsed (P=.54).

CONCLUSIONS

Using combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for up to 2 years, we did not find evidence of a sustained benefit. This finding does not support a significant role for Mycobacterium avium subspecies paratuberculosis in the pathogenesis of Crohn's disease in the majority of patients. Short-term improvement was seen when this combination was added to corticosteroids, most likely because of nonspecific antibacterial effects.

Paneth cells, defensins, and the commensal microbiota: A hypothesis on intimate interplay at the intestinal mucosa

Mucosal surfaces are colonized by a diverse and dynamic microbiota. Much investigation has focused on bacterial colonization of the intestine, home to the vast majority of this microbiota. Experimental evidence has highlighted that these colonizing microbes are essential to host development and homeostasis, but less is known about host factors that may regulate the composition of this ecosystem. While evidence shows that IgA has a role in shaping this microbiota, it is likely that effector molecules of the innate immune system are also involved. One hypothesis is that gene-encoded antimicrobial peptides, key elements of innate immunity throughout nature, have an essential role in this regulation. These effector molecules characteristically have activity against a broad spectrum of bacteria and other microbes. At mucosal surfaces, antimicrobial peptides may affect the numbers and/or composition of the colonizing microbiota. In humans and other mammals, defensins are a predominant class of antimicrobial peptides. In the small intestine, Paneth cells (specialized secretory epithelial cells) produce high quantities of defensins and several other antibiotic peptides and proteins. Data from murine models indicate that Paneth cell defensins play a pivotal role in defense from food and water-borne pathogens in the intestinal lumen. Recent studies in humans provide evidence that reduced Paneth cell defensin expression may be a key pathogenic factor in ileal Crohn's disease, a subgroup of inflammatory bowel disease (IBD), and changes in the colonizing microbiota may mediate this pathogenic mechanism. It is also possible that low levels of Paneth cell defensins, characteristic of normal intestinal development, may predispose premature neonates to necrotizing enterocolitis (NEC) through similar close links with the composition of the intestinal microbiota. Future studies to further define mechanisms by which defensins and other host factors regulate the composition of the intestinal microbiota will likely provide new insights into intestinal homeostasis and new therapeutic strategies for inflammatory and infectious diseases of the bowel.

A meta-analysis of broad-spectrum antibiotic therapy in patients with active Crohn's disease

OBJECTIVE

This meta-analysis of controlled clinical trials was conducted to evaluate whether the use of broad-spectrum antibacterial therapy is associated with improvement in the clinical symptoms of Crohn's disease (CD).

METHODS

The MEDLINE and SCOPUS databases were searched from 1966 through May 3, 2006, for clinical trials that evaluated the efficacy of broad-spectrum antibiotics in CD. The search terms were Crohn's disease and antibiotics, antimicrobial, metronidazole, ciprofloxacin, or cotrimoxazole. The reference lists of retrieved articles were reviewed for additional relevant studies. Clinical improvement (response, remission, or improvement in clinical and/or laboratory findings) was the key outcome of interest.

RESULTS

Six randomized, placebo-controlled clinical trials were included in the meta-analysis. Pooling of the results from these trials yielded an odds ratio of 2.257 (95% CI, 1.678-3.036; P < 0.001) for antimicrobial therapy compared with placebo in patients with CD.

CONCLUSION

The results of this meta-analysis suggest that broad-spectrum antibiotics improve clinical outcomes in patients with CD, although further trials are needed.

Current therapy of inflammatory bowel disease in children

Ulcerative colitis (UC) and Crohn disease (CD) are chronic intestinal inflammatory diseases that can present as bloody diarrhea, abdominal pain, and malnutrition. Collectively, these disorders are referred to as inflammatory bowel disease (IBD). All patients with IBD share a common pathophysiology. However, there are a number of developmental, psychosocial, and physiologic issues that are unique to the approximate, equals 20% of patients that present during childhood or adolescence. These include the possibility of disease-induced delays in linear growth or physical development, differences in drug dosing, and the changes in social and cognitive development that occur as children move from school-age years into adolescence and early adulthood. Gastroenterologists caring for these children must therefore develop an optimal regimen of pharmacologic therapies, nutritional management, psychologic support, and properly timed surgery (when necessary) that will maintain disease remission, minimize disease and drug-induced adverse effects, and optimize growth and development. This article reviews current approaches to the management of patients with UC and CD and highlights issues specific to the treatment of children with IBD. The principal medical therapies used to induce disease remission in patients with UC are aminosalicylates (for mild disease), corticosteroids (for moderate disease), and cyclosporine (ciclosporin) (for severe disease). If a patient responds to the induction regimen, maintenance therapies that are used to prevent disease relapse include aminosalicylates, mercaptopurine, and azathioprine. Colectomy with creation of an ileal pouch anal anastomosis (J pouch) has become the standard of care for patients with severe or refractory colitis and results in an improved quality of life in most patients. Therefore, the risks associated with using increasingly potent immunosuppressant agents must be balanced in each case against a patient's desire to retain their colon and avoid a temporary or potentially permanent ileostomy. Decisions about drug therapy in the management of patients with CD are more complex and depend on both the location (e.g. gastroduodenal vs small intestinal vs colonic), as well as the behavior of the disease (inflammatory/mucosal vs stricturing vs perforating) in a given patient. Induction therapies for CD typically include aminosalicylates and antibiotics (for mild mucosal disease), nutritional therapy (including elemental or polymeric formulas), corticosteroids (for moderate disease), and infliximab (for corticosteroid-resistant or fistulizing disease). Aminosalicylates, mercaptopurine, azathioprine, methotrexate, and infliximab can be used as maintenance therapies. Because surgical treatment of CD is not curative, it is typically reserved for those patients either with persistent symptoms and disease limited to a small section of the intestine (e.g. the terminal ileum and cecum) or for the management of complications of the disease including stricture or abdominal abscess. When surgery is necessary, maintenance medications administered postoperatively will postpone recurrence. Patients with UC and CD are at risk for the development of micronutrient deficiencies (including folate, iron, and vitamin D deficiencies) and require close nutritional monitoring. In addition, patients with UC and CD involving the colon are at increased risk of developing colon cancer, and should be enrolled into a colonoscopy surveillance program after 8-10 years of disease duration.

Antibiotic therapy for Crohn's disease: a review

Increasing evidence suggests that gut bacteria play a pathogenic role in Crohn's disease (CD), providing a rationale for the use of antibiotics in the primary treatment of the disease. While there are data to suggest that antibiotics may be effective in treating active luminal, particularly colonic, and/or perianal CD, evidence for their use in these settings is hampered by the lack of well-designed, adequately powered, placebo-controlled trials. Furthermore, although nitroimidazole antibiotics have been shown to reduce postoperative recurrence following ileocolonic resection, their use is limited by side effects. There is a current need for rigorous multicentre studies looking into the role of antibiotics in treating perianal and luminal CD, as well as a need for the large-scale assessment of novel antibiotics, with low systemic absorption, which may improve patient tolerance.

The role of microbes in Crohn's disease

Despite decades of research, the etiology of Crohn's disease (CD) remains unknown. Its pathogenesis may involve a complex interplay between host genetics, immune dysfunction, and microbial or environmental factors. Microorganisms, including pathogens and members of the indigenous microbiota, may initiate or propagate the inflammatory process in CD. The pathogenesis of CD has been difficult to study, owing to the broad spectrum of typically nonspecific clinical manifestations, the complexity of environmental and genetic factors, the lack of an accurate model of disease, and the limitations of microbiological methods. A more useful and relevant paradigm for the etiology of CD might be based on the idea of a pathogenic microbial community profile and might emphasize the role of interactive sets of microbes, rather than the role of individual organisms. We review how microbes may participate in the pathogenesis of CD and how they may inappropriately activate the mucosal immune system in genetically predisposed individuals.

A possible link between Crohn's disease and ankylosing spondylitis via Klebsiella infections

Crohn's disease (CD) is an immune-mediated gastrointestinal inflammatory disease, which could arise from an interplay between genetic and environmental factors. Klebsiella microbes were suggested to have a vital role in the initiation and perpetuation of the disease through the mechanism of molecular mimicry. This proposition is based on the results of various studies where significantly elevated levels of antibodies against the whole bacteria or preparations from Klebsiella microbes and antibodies to collagen types I, III, IV, and V were detected in patients with CD and patients with ankylosing spondylitis (AS). Molecular similarities were found between Klebsiella nitrogenase and HLA-B27 genetic markers and between Klebsiella pullulanase and collagen fibers types I, III, and IV. Furthermore, significantly positive correlations and cross-reactivity binding activities were observed between anti-Klebsiella and anticollagen antibodies among patients with CD and AS. Early treatment of CD patients with anti-Klebsiella measures is proposed, which may involve the use of antibiotics and low starch diet together with other traditionally used immunomodulatory, immunosuppressive, or biologic agents.

Conventional therapy for Crohn’s disease

Crohn’s disease (CD) is a multifactorial disorder of unknown cause. Outstanding progress regarding the pathophysiology of CD has led to the development of innovative therapeutic concepts. Numerous controlled trials have been performed in CD over the last years. However, many drugs have not been approved by regulatory authorities due to lack of efficacy or severe side effects. Therefore, well-known drugs, including 5-ASA, systemic or topical corticosteroids, and immunosuppressants such as azathioprine, are still the mainstay of CD therapy. Importantly, biologicals such as infliximab have shown to be efficacious in problematic settings such as fistulizing or steroid-dependent CD. This review is intended to give practical guidelines to clinicians for the conventional treatment of CD. We concentrated on the results of randomized, placebo-controlled trials and meta-analyses, when available, that provide the highest degree of evidence. We provide evidence-based treatment algorithms whenever possible. However, many clinical situations have not been answered by controlled clinical trials and it is important to fill these gaps through expert opinions. We hope that this review offers a useful tool for clinicians in the challenging treatment of CD.

Use of antibiotics in the treatment of inflammatory bowel disease

An increasing amount of evidence suggests that enteric flora may have a role in the pathogenesis of inflammatory bowel disease (IBD). Patients with IBD appear to have an altered composition of luminal bacteria that may provide the stimulus for the chronic inflammation characterizing IBD. The suspected role of bacteria in the pathogenesis of IBD provides the rationale for using agents, such as antibiotics, that alter the intestinal flora. However, there remains much uncertainty about the optimal use of antibiotics in the treatment of Crohn's disease, ulcerative colitis, and pouchitis. This article reviews the literature and presents a clinical model for the use of antibiotics in IBD.

Antibiotics and probiotics in treatment of inflammatory bowel disease

Many experimental and clinical observations suggest that intestinal microflora plays a potential role in the pathogenesis of inflammatory bowel disease (IBD). Manipulation of the luminal content using antibiotics or probiotics represents a potentially effective therapeutic option. The available studies do not support the use of antibiotics in ulcerative colitis (UC). Antibiotics are effective in treating septic complications of Crohn’s disease (CD) but their use as a primary therapy is more controversial, although this approach is frequently and successfully adopted in clinical practice.

There is evidence that probiotic therapy may be effective in the prevention and treatment of mild to moderate UC. In contrast, a lack of successful study data at present precludes the widespread use of probiotics in the treatment of CD.

Both antibiotics and probiotics appear to play a beneficial role in the treatment and prevention of pouchitis and further trials are warranted to fully quantify their clinical efficacy.

Antibiotic treatment of Crohn's disease: results of a multicentre, double blind, randomized, placebo-controlled trial with rifaximin

BACKGROUND

Clinicians often employ antibiotics in Crohn's disease. Rifaximin is active against bacteria frequently found in the intestinal mucosa of Crohn's disease patients.

AIM

To evaluate the difference in efficacy between once and twice/daily oral administration of rifaximin and placebo in the treatment of active Crohn's disease.

METHODS

We enrolled 83 patients with mild-to-moderate Crohn's disease and randomized to three treatments for 12 weeks: Group A (rifaximin 800 mg o.d. + placebo), Group B (rifaximin 800 mg b.d.) and Group C (placebo b.d.).

RESULTS

Clinical remission was achieved by 52% of Group B, 32% (A) and 33% (C). Clinical response was seen in 67% (B), 48% (A) and 41% (C), without reaching a statistically significant difference. Treatment failures were: 4% (B), 12% (A) and 33% (C), (P = 0.010). Remission and response rates of rifaximin 800 mg b.d. were significantly higher than those of placebo and rifaximin 800 mg o.d. in patients with elevated C reactive protein values (P < 0.05).

CONCLUSIONS

Rifaximin 800 mg b.d. was superior to placebo in inducing clinical remission of active Crohn's disease. Although this difference was not statistically significant, the number of the failures in the placebo group was significantly higher than those who received rifaximin 800 mg b.d.